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fping sometimes returns dupe pings on host with lots of ICMP activity #191

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mayheart opened this issue Jul 16, 2020 · 7 comments
Closed

fping sometimes returns dupe pings on host with lots of ICMP activity #191

mayheart opened this issue Jul 16, 2020 · 7 comments
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@mayheart
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Hi there,

I've ran into a weird issue with fping registering duplicated packets. This host has a lot ICMP activity going on, lots of HOST UNREACH, there's also fping sessions running in the background. If I limit the amount of ICMP activity, these duplicate issues go away.

/usr/bin/fping -e -q -c 3 -p 200 -t 500 192.168.94.154

192.168.94.154 : xmt/rcv/%loss = 3/3/0%, min/avg/max = 15.7/19.6/22.0

/usr/bin/fping -e -q -c 3 -p 200 -t 500 192.168.94.154

192.168.94.154 : duplicate for [0], 84 bytes, 54.9 ms [<- 192.168.94.102]
192.168.94.154 : duplicate for [1], 84 bytes, 54.7 ms [<- 192.168.94.102]
192.168.94.154 : xmt/rcv/%loss = 3/3/0%, min/avg/max = 14.3/14.5/14.8

/usr/bin/fping -e -q -c 3 -p 200 -t 500 192.168.94.154

192.168.94.154 : xmt/rcv/%loss = 3/3/0%, min/avg/max = 18.5/19.9/21.4

[tcpdump from the 2nd dupe ping. 192.168.94.102 was being fping'd in a separate process in the background]
14:23:30.088038 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 1, seq 0, length 64
14:23:30.102825 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 1, seq 0, length 64
14:23:30.118139 IP 192.168.94.137 > 192.168.95.174: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.124185 IP 192.168.94.137 > 192.168.94.102: ICMP echo request, id 1, seq 0, length 64
14:23:30.142943 IP 192.168.94.102 > 192.168.94.137: ICMP echo reply, id 1, seq 0, length 64
14:23:30.149838 IP 192.168.94.137 > 192.168.89.222: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.156188 IP 192.168.94.137 > 192.168.95.174: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.175882 IP 192.168.94.137 > 192.168.89.222: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.187189 IP 192.168.94.137 > 192.168.89.9: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.203772 IP 192.168.94.137 > 192.168.89.222: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.211093 IP 192.168.94.137 > 192.168.89.9: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.233026 IP 192.168.94.137 > 192.168.89.9: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.280678 IP 192.168.94.137 > 192.168.231.253: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.288266 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 1, seq 1, length 64
14:23:30.302885 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 1, seq 1, length 64
14:23:30.324312 IP 192.168.94.137 > 192.168.94.102: ICMP echo request, id 1, seq 1, length 64
14:23:30.324622 IP 192.168.94.137 > 192.168.231.253: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.343009 IP 192.168.94.102 > 192.168.94.137: ICMP echo reply, id 1, seq 1, length 64
14:23:30.368692 IP 192.168.94.137 > 192.168.231.253: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.488483 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 1, seq 2, length 64
14:23:30.492304 IP 192.168.94.137 > 192.168.93.205: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.502823 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 1, seq 2, length 64
14:23:30.512487 IP 192.168.94.137 > 192.168.93.205: ICMP 192.168.94.137 udp port 53 unreachable, length 68
14:23:30.524422 IP 192.168.94.137 > 192.168.94.102: ICMP echo request, id 1, seq 2, length 64

uname -a

Linux librenms 5.7.0-1-amd64 #1 SMP Debian 5.7.6-1 (2020-06-24) x86_64 GNU/Linux

fping --version

fping: Version 4.3
fping: comments to david@schweikert.ch

ifconfig vlan990

vlan990: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.94.137 netmask 255.255.255.240 broadcast 192.168.94.143
inet6 fe80::230:48ff:fedd:93d4 prefixlen 64 scopeid 0x20
ether 00:30:48:dd:93:d4 txqueuelen 1000 (Ethernet)
RX packets 3131050377 bytes 996169961741 (927.7 GiB)
RX errors 0 dropped 16 overruns 0 frame 0
TX packets 2848131375 bytes 395710959835 (368.5 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
@mayheart mayheart changed the title fping sometimes returns dupe pings fping sometimes returns dupe pings on host with lots of ICMP activity Jul 16, 2020
@mayheart
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Downgrading fping back to 4.2 completely fixed the duplicate ping issue.

@mayheart
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[4.3 binary (from source)]

14:52:29.735216 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 1, seq 0, length 64
14:52:29.748887 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 1, seq 0, length 64
14:52:29.935484 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 1, seq 1, length 64
14:52:29.949628 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 1, seq 1, length 64
14:52:30.135751 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 1, seq 2, length 64
14:52:30.152963 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 1, seq 2, length 64

[4.2 from debian]

14:52:34.561876 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 54885, seq 0, length 64
14:52:34.575538 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 54885, seq 0, length 64
14:52:34.762122 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 54885, seq 1, length 64
14:52:34.777432 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 54885, seq 1, length 64
14:52:34.962379 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 54885, seq 2, length 64
14:52:34.977410 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 54885, seq 2, length 64
14:52:35.442977 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 54886, seq 0, length 64
14:52:35.457478 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 54886, seq 0, length 64

It looks like the ICMP ID behavior was changed between 4.2 and 4.3. I suspect it's picking up ICMPs from other pings if they happen at the same second and have the same ID.

@schweikert
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This might be caused by 1486bf2

@schweikert
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@tycho FYI

@schweikert schweikert added the bug label Jul 16, 2020
@tycho
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tycho commented Jul 16, 2020

Yeah, I saw this in my own systems. I think you might need to cherry pick this from my tree: tycho@d2dda2d

@mayheart
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mayheart commented Jul 16, 2020 •
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Yeah, I saw this in my own systems. I think you might need to cherry pick this from my tree: tycho@d2dda2d

Can confirm with your patch the old behavior returns. I put the binary into test production, no duplicates generated.

15:52:55.918252 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 29008, seq 0, length 64
15:52:55.933546 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 29008, seq 0, length 64
15:52:56.118512 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 29008, seq 1, length 64
15:52:56.131581 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 29008, seq 1, length 64
15:52:56.318779 IP 192.168.94.137 > 192.168.94.154: ICMP echo request, id 29008, seq 2, length 64
15:52:56.334724 IP 192.168.94.154 > 192.168.94.137: ICMP echo reply, id 29008, seq 2, length 64

@schweikert
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fixed in 57061af

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@tycho @schweikert @mayheart